Most vacuums come with a tube that works with several including attachments so that you can clean areas the vacuum, itself, can't go. These attachments are still too large to clean out your keyboard or parts of your computer, but you can solve that properly with the aid of a ketchup squeeze bottle top.

Tumblr user mintfish points to this clever solution. You can't use the top of a standard squeeze bottle that you'd buy in the store, but rather the old-fashioned kind you'd find at a classic diner. (See the picture above for an example). In some cases the top might fit right on, but you may have to tape it in the event your vacuum tube is a little smaller. Either way, once you have the top adhered you can use it to vacuum small areas like between your keyboard. Of course, there are plenty of other options for keybord cleaning, too.